The present invention relates generally to printers, and, more specifically, to paper feeding therein.
Laser printers are manufactured in different models by different manufacturers and offer different performance. Printing paper may be stored in the printer in various forms of trays.
One form of tray is a drawer which slides horizontally into and out of a corresponding compartment in the printer. The drawer tray has a central well or receptacle in which a stack of printing paper of various composition may be held.
The drawer is closed during operation, and pickup rollers are moved into position atop the stack of paper for initially driving individual sheets into the feedpath of the printer. As the individual sheets leave the tray, one or more drive rollers begin the sheet transport through the printer for printing any desired information thereon and ejecting the printed sheet in an output tray for recovery.
A printer may include one or more stacked drawer trays with or without duplexing capability for feeding the sheets through the printer for printing one or both sides thereof as desired. The trays may have different configurations and capacity for holding the sheets, and have pickup and drive rollers specifically configured therefor.
Besides plain paper sheets for use in the printers, laminated form sheets may also be transported therethrough for printing. A laminated sheet typically includes a base sheet laminated to a liner by pressure sensitive adhesive and silicone release agent therebetween in a typical example. The liner may extend for the full configuration of the base sheet, or may cover only a small portion thereof depending upon the nature of the particular sheet.
For example, a pharmacy script form includes a single ply form sheet integrated with an extension thereof in a two-ply laminate with a release liner. The base sheet above the liner is die cut to define one or more removable labels initially bonded by the pressure sensitive adhesive to the liner. Both the form sheet and the individual labels can be printed in one pass through the printer for improving the typical pharmaceutical transaction.
The problem of undesirable curling during transport in the printer has been discovered in the use of various types of sheets in a specific commercially available laser printer, but not in other commercially available laser printers. In this printer, one corner of the form sheet can experience excessive curling during initial feeding of the sheet from the paper tray, with the corner being bent over backwards in dog-ear fashion upon engaging the first drive roller in the feedpath. This sheet curling can lead to sheet skewing through the printer feedpath, and even jamming therein. And, this curling problem can occur for various types of sheets of various composition.
Accordingly, it is desired to provide a remedy for undesirable sheet curling in a pre-existing commercially available printer without requiring changes thereof by the original equipment manufacturer.